2011 Fresh River Voyage of Discovery :: Learning Pages :: Second Leg

2011 Fresh River Voyage of Discovery banner

When traveling through uncharted waters, one of the most basic questions a ship's crew needs to be able to answer is also one of the most important: How deep is the water? In fact, as Juet's journal entries show, Captain Hudson and his crew repeatedly faced the danger of running aground while exploring the river that would later bear his name.

When in doubt, we take soundings (measure the water's depth) with the same tool Hudson's crew would have used: a lead line (or sounding line). Flags attached to the lead line mark depth in 6-foot increments (fathoms). The Half Moon has a draft of 8-1/2 feet (extending that far underwater), so it needs at least a fathom and a half of water to stay clear of the bottom.

Monitoring water depth is just as important for us on board the Replica Ship Half Moon. Of course, in 21st century the Connecticut River has been throughly charted and (unlike Captain Hudson) we have experience navigating this river, but that doesn't mean there are no uncharted waters for us to explore.

In Hudson's day, crews would even use their lead lines to take samples of the river bottom. They could fill a small hollow on the bottom of the line's lead weight with tallow or grease, then see what stuck to this goo when they retrieved the line. Silt or sand made for a fine anchorage, but clean tallow warned of rocks lurking below, making anchorage dangerous if not impossible.

On this leg of the voyage, the research team of Hayley, Jason, and Morgan studied height of tide and current speed for their presentation project on tidal patterns. Once we arrived at Constitution Island, we temporarily installed a depth marker on the shoreline. With assistant from Anchor Watch, the team then used the fixed depth finder to mark the tidal changes that occurred over a full 24-hour period.

Back to Top